Implantable devices for opening and closing tubular organs of the body such as in particular but not exclusively the urethra are used more particularly in the form of prostheses for the treatment of urinary incontinence, also being known as artificial sphincters. Such an arrangement uses closure means which act mechanically on the urethra and which perform the function of the natural sphincter muscle in the event of failure of the latter. Many different forms of such closure arrangements are known. For example Swiss patent specification No 463 015 discloses an implantable device for selectively opening and closing the urethra, which has clamping members that are movable towards each other to close off the urethra. The clamping members are subjected to the action of a spring and a magnet so that they can be actuated from the outside. A prosthesis is also known for male urinary incontinence (DE-GU 79 29 052), in which a cuff that surrounds the urethra permits it to be shut off by the application of a pressure thereto. The prosthesis disclosed in EP 144 699 B1 also includes a cuff which surrounds the urethra on the outside thereof, the opening or closed position of the prosthesis being produced by mechanical pressure from the outside or by liquid pressure. For that purpose the arrangement has an implanted pump with an implanted liquid reservoir.
In the above-indicated arrangements the urethra is selectively closed or opened by pressure from the exterior. However, even when very soft cuffs which act on the urethra with extreme gentleness are used as the means for closing off the urethra, necrotic damage to the urethra or the surrounding tissue with a good blood supply occurs after a comparatively short period of time, in the region of the closure member or cuff. The closure member then has to be removed to avoid aggravating the damage. It will be seen therefore that such an arrangement cannot provide a permanent solution to the problem of incontinence or even only a temporary solution for at least a relatively long period of time. A similar consideration also applies to the situation where other organs of the body are to be selectively opened or closed, for example blood vessels.
An incontinence valve is to be found in German patent specification No 41 35 502, which is formed by an elongate valve body with longitudinal bore therein, which valve body is to be introduced over its entire length into the urethra. The valve body has an open end and a closable end with a valve head. The urine is guided along the outside of the valve to at least one radially arranged communicating opening leading into the longitudinal bore, while the communicating opening can be selectively opened or closed by way of a shut-off device which is actuable from the distal end. Although that valve arrangement avoids the disadvantages of the above-discussed valves in which the urethra is compressed by a pressing force applied thereto from the outside thereof, further problems are still encountered. In particular it is not possible to insert a catheter through the valve body, as may be necessary in emergency situations and for investigation.